Basically there are two distinguishing types of reels. First, a simple paddle reel that only guides the harvesting good with tine-less paddle bars for the cutting section of the harvester. Second, a tine reel exists that has paddle tubes or bars with projecting steel or plastic tines.
Tine reels have won recognition in combine harvesters compared to simple paddle reels. Only the tine reels are able to guide laid grain or entangled harvesting goods securely to the cutting section. The tines are controlled such that they engage at the same angle. The tines maintain a nearly vertically downwards direction into the harvesting good in front of the machine. A controller adjusts the tine carriers, generally in form of tubes, by crank arms, that rotate the tine carrier along a corresponding curved path. The curved paths may be formed differently. The controller may always rotate the tine carrier in the same direction or may rotate, depending on the lay-out of the curved path, a one revolution magnitude back and forth. One crank arm is always rigidly connected to the tine carrier tube. Thus, the angle to the tine can be maintained and each of the several tine carriers of a reel takes up the same engagement angle relative to the harvesting good.
If the engagement angle of the tine of all tine carriers should be changed, the control curve must be adjusted.
Such tine carrier controls are known from DE 26 29 353 A1, U.S. Pat. No. 4,098,061 and U.S. Pat. No. 6,170,244 B1.
Most reels for combine harvesters have six tine carriers. It may be desirable to alternatively provide different angle positions of the tines relative to the harvesting good. This has the advantage, that with a corresponding reel rotational speed, the harvesting good can be guided to the cutting section by differently adjusted tines. Thus, it is an advantage, when a reel portion takes up the harvesting good in front of the knife line of the cutting section, for the following reel portion to push the material into the feed screw.
In other applications, for example in the harvest of sunflowers, no tines, but only the carrier tubes or tine carriers engage the harvesting good. Thus, in such an application, not all tines of the respective tine carriers have to be detached. Accordingly, it is advantageous to be able to rotate the tine carrier by 180° so that the tines, instead of pointing downwards, are directed upwardly not engaging the falling off sensitive harvesting good. Thus, they are not arranged in an engaging position.